Build the browser template on any docker base image

.github/workflows/on-pull-request-images.yml

@@ -87,20 +87,27 @@ jobs:
           docker exec sbx-boot /usr/sbin/sshd -T | grep -iEx 'permitrootlogin (prohibit-password|without-password|yes)'
 
   # Drukbox builds the browser as a template: browser.sh run on the default
-  # image of its docker provider, which every druks deploy sets to the sandbox
-  # image above.
+  # image of its docker provider. The deployment sets that image, so browser.sh
+  # must build on drukbox's stock image and on the sandbox image above.
   browser:
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        base: [ghcr.io/czpython/drukbox/sandbox:latest, druks-sandbox:pr]
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           persist-credentials: false
       - name: Build the sandbox image
+        if: matrix.base == 'druks-sandbox:pr'
         run: docker build --target sandbox --tag druks-sandbox:pr deploy/sandbox
       - name: Build browser.sh the way Drukbox builds a template
+        env:
+          BASE: ${{ matrix.base }}
         run: |
           printf '%s\n' \
-            'FROM druks-sandbox:pr' \
+            "FROM $BASE" \
             'COPY browser.sh /drukbox-setup.sh' \
             'RUN sh /drukbox-setup.sh && rm /drukbox-setup.sh' \
             | docker build --tag druks-browser:pr --file - backend/druks/browser/sandboxes

backend/druks/browser/sandboxes/browser.sh

@@ -1,6 +1,7 @@
 #!/bin/sh
-# Drukbox builds this as root on the default image of its docker provider: the
-# sandbox image (deploy/sandbox/Dockerfile), which has Node 22 and the druks user.
+# Drukbox builds this as root on the default image of its docker provider. The
+# deployment sets that image. It can be the sandbox image
+# (deploy/sandbox/Dockerfile), which already has Node 22 and the druks user.
 set -eu
 export DEBIAN_FRONTEND=noninteractive
 arch="$(dpkg --print-architecture)"
@@ -10,6 +11,10 @@ playwright_version=1.62.0
 apt-get update
 apt-get install -y --no-install-recommends ca-certificates curl gnupg
 install -d -m 0755 /etc/apt/keyrings
+curl -fsSL https://deb.nodesource.com/gpgkey/nodesource-repo.gpg.key \
+    | gpg --yes --dearmor -o /etc/apt/keyrings/nodesource.gpg
+echo "deb [arch=$arch signed-by=/etc/apt/keyrings/nodesource.gpg] https://deb.nodesource.com/node_22.x nodistro main" \
+    > /etc/apt/sources.list.d/nodesource.list
 # Real Google Chrome, so the login browser presents Chrome's fingerprint and not
 # Chromium's. A login gate reads the difference.
 curl -fsSL https://dl.google.com/linux/linux_signing_key.pub \
@@ -19,7 +24,7 @@ echo "deb [arch=$arch signed-by=/etc/apt/keyrings/google-chrome.gpg] https://dl.
 apt-get update
 apt-get install -y --no-install-recommends \
     fonts-liberation fonts-noto-cjk fonts-noto-color-emoji \
-    google-chrome-stable tzdata x11vnc xvfb
+    google-chrome-stable nodejs tzdata x11vnc xvfb
 rm -rf /var/lib/apt/lists/*
 
 install -d -m 0755 /opt/druks-browser
@@ -41,6 +46,7 @@ install -d -m 0755 /etc/opt/chrome/policies/managed
 echo '{"CommandLineFlagSecurityWarningsEnabled": false}' \
     > /etc/opt/chrome/policies/managed/druks.json
 
+id druks >/dev/null 2>&1 || useradd --create-home --shell /bin/bash druks
 install -d -m 0700 -o druks -g druks /work/session
 # Xvfb runs as druks and cannot make this directory sticky itself.
 install -d -m 1777 /tmp/.X11-unix

backend/druks/browser/sandboxes/goss.yaml

@@ -1,5 +1,5 @@
 # The boot contract of the browser template: the drukbox base entrypoint seeds
-# the ``druks`` user of the sandbox image, and /work/session belongs to it.
+# the ``druks`` user, and /work/session belongs to it.
 # dgoss checks it in CI with DRUKBOX_SSH_USER=druks and
 # DRUKBOX_AUTHORIZED_KEY="ssh-ed25519 AAAA goss".
 file: